ET 743 (Yondelis) in Men With Advanced Prostate Cancer

The main purpose of this study is to find out what effects (good or bad) trabectedin (ET743) has on men with advanced prostate carcinoma.

* Treatment with trabectedin will be given once a week for three consecutive weeks with one week of no treatment. This four week period constitutes one cycle. * Trabectedin is given as an infusion through a central venous catheter and is administered over 3 hours. * On day 1 of each cycle a history, physical exam and blood tests will be performed and trabectedin will be administered. * On day 8 and day 15 of each cycle blood work will be performed and trabectedin will be administered. * Patients will continue to receive trabectedin as long as there is no disease progression or unacceptable side effects. * Scans (CT, MRI or bone) or x-rays may be done while the patient is on the trial at the discretion of the physician.